Gun perforator



Oct. 22, 1940. I I; J. MQCULLOUGH GUN PERFORATOR Filed Flb. 27, 1939 3Sheets-Sheet l 4 6 c a a J24 J/Vaduuouam, IN VENTOR.

A TTORNEY Oct. 22, 1940. l. J. McCULLOUGH 2,218,802

' mm Paar-canon Filed Feb. 27, 1939 3 Sheets-Sheet 2 [QA JMC'Cz/LLm/am ATTORNEY Patented Oct. 22, 1940 UNITED STATES PATENT OFFICE 22 Claims.

My invention relates to guns of the type adapted to be lowered into awell casing wherein the firing of the gun will drive projectiles outthrough the wall of the casing to perforate the same, and for the samegeneral purpose and use as the inventions of my copending applicationsentitled Method and apparatus for perforating well casing, Serial No.80,548, filed May 19, 1936, and Gun perforator, Serial No. 129,624,filed March 8, 1937. Itrelates in particular to improvements inperforating guns of this general character to enable the making of a gunof such small diameter that it may be employed in small diameter casing.

It is an object of the invention to provide a perforating gun having agun body of small diameter, yet with gun bores of such lengths thatsufficient projectile velocity will be attained to readily accomplishpenetration of the casing wall.

vide a perforating gun wherein the firing powder chamber for theexplosive is placed to one side of the gun bore, or, in other words, isoffset from the gun bore in the direction of the axis of the gun body sothat a maximum portion of the diameter of the gun body may be utilizedfor the gun bore which receives the projectile. Bythis expedient the gunbore is given sufiicient length to assure ample muzzle velocity for theprojectile so that it will readily penetrate the wall of the casing.

It is a further object of the invention to provide a perforating gunhaving a body so formed thatth e explosive charges and the projectilesmay be readily placed and replaced to charge and recharge the gun.

It is a further object of the invention to provide a perforating gunwherein the gun body is formed by a plurality of body sections securedtogether in end to end relation, with the powder chambers so placed asto be exposed for charging when the gun body sections are disconnected,and which powder chambers are closed when the sections are securedtogether in end to end relation.

It is a further object to provide a perforating gun having simple andeffective means whereby an ignition flame may be carried from one powderchamber to another without material loss of explosive force or pressureresulting from the firing of explosive charges in the powder chambers.

It is a further object of the invention to provide a perforating gun ofthe general character hereinbefore described wherein the explosive It isalso an object of the invention to procharges in the powder chambers arefired by flames which pass'through ignition passages and wherein suchpassages are provided with restraining means to minimize the loss ofexplosive force or pressure through the ignition passages.

It is a further object of the invention to provide a perforating gunhaving a simple form of firing means which is positive in its operationand which is so formed that the parts which are deteriorated in theoperation of the gun may be readily replaced.

A further object of the invention is to provide an improved lock for thefiring means automatically operative to prevent inadvertent oraccidental operation of the firing device during the time the gun isbeing manipulated in the well.

A further object of the invention is to provide a gun body having asuspension means extended upwardly therefrom, this extensionhaving afiring pin in the lower part thereof and an anvil supported on the upperportion thereof in position to be struck by a hammer which descends fromthe top of the well along the cable by which the perforating gun issuspended, locking means for the firing device disposed in the lowerportion of the extension, and an actuating means for the locking meanswhich is slidable on the upper and lower portions of the extension andis positioned so as to surround and protect exposed parts of the firingdevice.

Further objects and advantages of the invention will be brought out inthe following part of the specification.

Referring to the drawings which are for illustrative purposes only:

Fig. 1 is a partly sectioned fragmentary view showing a preferred formof my perforating gun being lowered into a casing.

Fig. 2 is a View similar to Fig. 1 showing the gun being raised in thecasing.

Fig. 3 is an enlarged fragmentary section of the portion of the deviceindicated at 3 in Fig. 1.

Fig. 4 is an enlarged fragmentary section of the succeeding portion ofthe device indicated at 4 in Fig. 1.

Fig. 5 is an enlarged fragmentary section of the portion of the deviceindicated at 5 in Fig. 1.

Fig. 6 is an enlarged cross-section taken substantially on the planeindicated by the line 6-6 of Fig. 3.

Fig. 7 is an enlarged fragmentary section on the plane indicated by theline 'l'| of Fig. 2.

Fig. 8 is a sectional view similar to Fig. 3,

but showing the positions of the parts after actuation of the firingdevice of the periorator gun.

Fig. 9 is a fragmentary section similar to Fig. 4 showing the positionof the firing pin after actuation of the firing device.

In Fig. 1 I show the well casing ID with a perforating gun therein. Thisgun H is described as having a gun body I2 comprised of an upper gunbody section |3, a plurality of intermediate gun body sections l4, and alower gun body section IS. The upper part of the gun II is referred toas a suspension means l8 for the gun body l2, this suspension means Itprojecting upward from the body l2 and having a cable |1 securedthereto, by which the perforating gun may be moved in the casing III toa desired.

position for firing.

As best shown in Fig. 4, the upper body section l3 comprises a bar ofdurable metal, such as alloy steel, having a threaded opening |3 leadingin from a side thereof to receive a threaded gun barrel I9 having a gunbore 20 in which a bullet or projectile 2| is placed, this projectile 2|carrying near its rear or inner end a metal collar 22 which serves as ashearable or separable flange for the projectile. At the bottom of thethreaded opening there is a radial shoulder 23, and, communicating withthe inner end of the opening |8 there is a recess 24 in centralizedrelation to the inner end of the bullet 2|.

The upper end of the body section I3 is connected to the lower portion25 of the suspension means l6 by means of a pin and box Joint 21, theupper end of the section |3 having a threaded box 29 which receives athreaded pin 29 formed on the lower end of the portion 25. Extendingdownward from the box 28 there is an opening 30 having. an upper section3| and a lower section 32, the upper section 3| being of larger diameterthan the lower section 32 and receiving a body or plug 33 whichessentially closes the lower section 32 to form a powder chamber 34 inwhich a charge of explosive 35 is placed. A passage 35 connects thepowder chamber 34 with the recess 24 to transmit to the rear end of thebullet 2| the explosive force or pressure resulting from the firing ofthe charge 35 in the chamber 34.

As shown in Fig. 5, the gun body sections l4 and I are joined inconsecutive order to the upper section l3 by means of pin and box joints25, the sections l3 and I4 each having a threaded pin 29a projectingdown from the lower ends thereof, and the sections l4 and I5 having athreaded box 29 at the upper end thereof to receive the pin of the upperadjacent section. Like the upper section l3, the sections I4 and I5 eachhave a laterally extended gun bore 20 preferably formed by a barrel l9which is threaded into an opening I8. At the inner end of each gun bore2|! there is a recess 24 connected by a passage 36 with a powder chamber34 formed at the inner end of a threaded box 28.

Means are provided whereby heat and pressure resulting from the firingof a charge in one of the chambers 34 will result in the firing of thesecharges in the remaining chambers. For example, the firing of theexplosive charge 35 in the upper chamber 34, Fig. 4, will result in thefiring of the charges in the remaining chambers 34, Fig. 5. Toaccomplish this purpose I provide lgnition passages which seriallyconnect the consecutive powder chambers 34. As shown in Figs. 4 and 5such ignition passages include the passages 36 and passages 31 whichextend downward amasoa from the recesses 24 of the sections l3 and I4through the threaded pins 290 01 such sections. Each passage 31 has anenlarged threaded section 33 to receive a restraining means 39comprising a threaded member having an orifice 43 of small diameter andconsiderable length through which the heat and pressure, or ignitionfiam'e, from the firing of a charge in one chamber 34 is transmitted tothe charge in the next lower chamber 34. The restraining means 39 isreplaceable and for this purpose has a head 4| suitably prepared. aswith a socket 42. to receive a wrench.

Replaceability of the restraining means 39 is im-v portant in thepractice of the invention, for the following reason. The passage 40 mustbe only of such diameter that it will permit flame and pressure to passtherethrough to ignite the assoelated succeeding firing powder charge ina chamber 34, and it must be of such limited diameter that there will beonly a relatively small escape of pressure therethrough when the firingpowder charge is ignited. After a period of use .this passage 49 burnsout to larger diameter so that its effectiveness as a restraining meansis reduced, and so that the operation of the gun will be maintained athigh eificiency the restraining means 39 are replaced whenever theopenings 40 therethrough have become enlarged to a predetermined maximumvalue.

When the charge 35 in the upper powder chamber 34 is ignited, by meanswhich will be herein-,

after described in detail, the combustion products therefrom pass downthrough the passage 35, Fig. 4, to the recess 24 to discharge the bullet2|, and some of these superheated combustion products pass down throughthe passage 31 to the charge 350, such ignition gases or fiame beingunder restraint of the orifice 40 of the restraining member 39 which isdisposed between the charges 35 and 35a. The passage of the ignitionflame, or pressure, or both to the charge 35a results in the ignitionthereof, and the products of combustion resulting from this ignitionpass principally downward through the associated passage 35. A smallproportion of the combustion products will pass upward from the charge35a through the orifice 40 of the restraining means 39 placed directlythereabove, but the restraining effect of the orifice 40 is such thatthe loss of combustion products therethrough is kept relatively smalland accordingly does not materially affect the discharge of the bullet2| from the gun bore 20 which is directly associated with the charge ofexplosive 35a. In accordance with the foregoing explanation, theignition effect is carried downward from one powder chamber to the next,with the result that all of the bullets 2| are discharged from the gun.Each restraining means 39 serves in dual capacity. For examle, when thecharge 35 shown in Fig. 9 is fired, the restraining means 39 positionedtherebelow protects the succeeding charge 35a, Fig. 5, from the fullforce of the explosion of the charge 35. The passage 40 of suchrestaining means merely permits an ignition fiame and pressure to passto the charge 350 to ignite the same. When this charge 35a is thusignited the restraining means 39 thereabove serves to prevent undue lossof explosive pressure in upward direction. Accordingly, the restrainingmeans 39 acts to restrain a firing charge against its back pressure andagainst the explosive force of another firing charge.

The lower portion 25 of the suspension means l6 has a tubular portion 43projecting upward therefrom, with internal threads 44, Fig. 3, at

the upper end thereof to receive a threaded projection 45 on the lowerend of the upper section 46 of the suspension means IS. The uppersection 46 includes a fiange 41 which rests against the upper end of thetubular wall 43 and an essentially cylindrical body 48 above the flange41, this body 48 having a threaded pin 49 projecting therefromto'receive a cable socket 58 by which the cable I1 is secured to thesuspension means.

Directly above the flange 41, the body 48 has a diametral, verticallyelongated opening 5|, and above the opening 5| there is a shallowdepression or channel 52 of annular form in the body 48. Slidable on theupper portion of the body 48 and the cable socket 58, I provide atubular member 52 which is referred to as the anvil for the reason thatit is adapted to be struck, by a tubular weight which is dropped downthe cable l1 so as to strike the upper end 53 of the member 52 and to bethereby driven forcibly downwarl to accomplish the result of actuatingthe firing means of the perforating gun. The anvil 52 may be consideredas forming a part of the structure of the suspension means l6, althoughit has limited movement relative to the remaining parts. To limit theupward movement of the member 52, it is provided with screws 54,threaded through the lower portion thereof into engagement with thebottom wall of the annular channel 52'. It is preferable to set thesescrews 54 tightly against the bottom wall of the channel 52' so that thepressural engagement thereof with the body 48 will hold the member 52 inraised position during the lowering of the perforating gun into thewell.

When the anvil 52 is driven downward, the movement thereof istransmitted through a removable crossbar 55 to the upper end 56 of afiring pin 51, which extends through the lower section 25 of thesuspension means I6 and through the threaded pin 29 thereof. The firingpin 51 comprises an upper part 58, which is a permanent part of theperforator gun, and a lower replaceable part 59 of smaller diameter. Thepermanent part 58 of the firing pin 51 extends through an opening 68 inthe threaded projection 45 and on its lower end has a guide head 6|which is slidable in the lower part of the tubular portion 43. This head6| has a threaded portion 62 to receive a threaded inverted cup 63 bywhich the replaceable pin part 59 is connected to the permanent firingpin part 58.

The threaded pin 29 of the joint 21, Fig. 4, has an opening 64 throughwhich the firing pin part 59 passes, this opening 64 being provided withpacking means 65 compressed by a gland 66 which threads into the lowerpart of the pin 29. The lower end 61 of the member 59 is sharpened, andis positioned so as to project into a threaded counterbore 68 formed inthe removable block 33, to hold in the opening 69 of this block 33 anigniting device 18 which may consist of a powdercharged cartridgepositioned so that the discharge therefrom will be directed downwardagainst the charge 35 placed in the upper firing powder chamber 34. Thefiring pin 51 is normally held in raised position, as shown in Figs. 3and 4, by means of a shear pin 1| which is passed through an opening 12near the upper extremity of the firing pin part 58 and in a position torest against the upper face of the flange 41. During transportation andhandling of the perforator gun, the crossbar 55 is removed from theposition in which it is shown in Fig. 3 so that at this time there willbe no connection between the lower end of the anvil 52 and the upper end56 of the firing pin 51. When the perforator gun is in position to belowered into the well casing, the crossbar 55 is placed in operativeposition, and the cotter pins 13, Figs. 3 and 6, may be placed in theends thereof adjacent the ends of the lateral opening 5|, to secure thecrossbar 55 against removal.

When it is desired to fire the gun, a tubular weight or hammer is placedon the upperportion of the cable I1, and is released so that it willdrop along the cable l1 and strike against the upper end 53 of the anvil52, as indicated by dotted line 14 in Fig, 8, the impact of this hammeragainst the anvil 52 driving the same downward to a position such asshown in Fig. 8, forcing the crossbar 55 downward and transmittingmovement to the firing pin 51, to shear the pin 1|, and drive the lowersharpened end 61 of the firing pin pairt'59 down against the cartridge18, as shown in Fig. 9. The flash of the cartridge 18 will ignite theupper charge 34 and each consecutive charge will be ignited through theignition passages which serially connect the powder chambers of thedevice. After removal of the gun from the well, the pin and box joints21 and 26 may be broken, exposing the powder chambers so that they maybe recharged. The gun barrels |9 may be unscrewed from the threadedopening |8 so as to be recharged with projectiles 2|. After a number ofoperations of the device it will be found necessary to replace therestraining members 39 because .of the burning out which produces anenlarging of the orifices 48 thereof.

As clearly shown in Figs. 4 and 7, the lower portion 25 of thesuspension means l8 has a lateral opening 11 positioned above andclose'to the threaded pin 29. This opening 11 provides access to the cup63 which may be regarded as a removable portion of the head 6| forraising the same and forinserting a new shear pin 1|. Screws 18, nearthe upper end of the tubular wall 43, secure the upper endof a leafspring 19 'which extends downward along the tubular wall 43 and has adog 88 secured thereto in a position to project into the lower part ofthe opening 11. When the firing pin 51 is supported in raised positionby the shear pin 1|, the lower face 8| of the cup 63 will be in a planeabove the upper face 82 of the dog 88 so that inward pressure againstthe dog 88 will move the same into a position, such as shown in Fig. '1,wherein the inner portiton 83 of the dog 88 will lie under the cup 63 soas to prevent downward movement of the firing pin 51. The lock thusprovided, is automatically operated when the gun is moved upward in thewell as the result of the relative movement of a resilient engager ordrag 84 which, as shown in Figs. 1 and 2, has bow springs 85 whichresiliently engage and drag along the wall of the casing H1. The lowerends of the bow springs 85 are connected to a sleeve 86 which isslidable on the lower portion of the suspension means l6, and the upperends of the bow springs 85 are connected to a sleeve 81 which surroundsthe upper portion of the suspension means I6, such sleeve 81 beingfreely slidable on the anvil 52. After the engager 84 is placed on thegun, so that the lower sleeve 86 thereof surrounds the tubular portion43, an upper stop is placed at the upper end of the tubular portion 43to limit the upward movement of the engager 84. Such stop may consist,as shown in Figs. 3 and 6, of a U- shaped spring clip 88 which issnapped into a circumferential groove 88 formed in the tubular wall nearthe upper end thereof.

when the perforating gun H is being lowered in the casing It, as shownin Fig. 1, the engager I will be in raised position with the lowersleeve .6 in engagement with the stop 88 and also in a position abovethe upper end of the spring I, as shown in Fig. 3. Should it becomenecessary to raise the gun Ill without having first fired the same,upward movement of the gun ll resulting from a pull on the cable II willmove the suspension means l8 upward through the 'engager 84 so as tocause the engager 84 to assume the position thereof shown in Fig. 2. Thesleeve 86, inmoving relatively downward into the position in-which it isshown in Fig. 2, will force the spring 18 inward and will ride into aposition surrounding the dog 80 so as to force this dog 80 inward to aposition such as shown in Fig. 7, wherein it will be positioned to lockthe firing pin 51 against downward movement. When the firing device isthus locked, there will be no danger of inadvertent discharge of the gunas it is lifted from the well.

I claim as my invention:

1. In a well perforating gun of the character described, the combinationof: a body having a plurality of gun bores with projectiles therein,'

firing charge chambers communicating with the ends of said gun bores,and passages serially connecting said firing charge chambers, therebeing restraining means in said passages between said firing chargechambers; firing charges in said firing charge chambers; and means toeffect a firing of a firing charge in at least one of said firing chargechambers, said restraining means each being so formed and placed as toserve to conduct products of explosion from the firing of a charge inone of said chambers to ignite the firing charge in the next succeedingfiring charge chamber, and to restrain loss of explosion products fromthe associated firing charge which has been fired.

2. In a well perforating gun of the character described, the combinationof a gun body having a plurality of gun bores with projectiles therein,firing charge chambers connected to the inner ends of said gun bores, aseparate firing charge isolated in each of said firing charge chambers,means for effecting a firing of at least one of said firing charges, andmeans serially connecting said firing charge chambers, said last namedmeans each comprising a passage through which the products resultingfrom the firing of a firing charge on one side thereof will pass to thefiring charge on the opposite side thereof to effect a firing of thesame. and each of said last named means restraining the reverse flow ofexplosion products from a firing charge chamber associated therewith.

3. In a perforating gun of the type adapted to be lowered into a wellcasing, the combination of: a body comprising a plurality of sectionshaving means for connecting them in end to end relation, each of saidsections having means forming a gun bore toreceive a projectile, apowder chamber connected to the inner portion of said gun bore, andfiring duct means for exploding a charge in said powder chamber, saidfiring duct means being operatively connected when said sections areconnected in end to end relation.

4. In a perforating gun of the type adapted to be lowered into a wellcasing, the combination of: a gun body comprising a plurality ofsections with associated means for connecting them in end to endrelation: each of said sections having a means forming a gun bore toreceive a projectile, a powder chamber. axially offset from said gunbore, and a passage connecting said powder chamber with the inner end ofsaid gun bore; and means operative to fire the charges in said powderchambers. v

5. In a perforating gun of the type adapted to be lowered into a wellcasing, the combination of: a body of relatively small diameter havingmeans to form therein a gun bore the outer end of which communicateswith the side wall of said body, a powder chamber spaced axially fromsaid gun bore, and a passage connecting said powder chamber and theinner end of said gun bore; and means to explode a charge in said powderchamber.

6. In a perforating gun of the character described, the combination of aplurality of body sections connected in end to end relation, certain ofsaid body sections which are connectedin consecutive order having alateral gun bore to receive a projectile, a firing charge chamber havingcommunication with the inner end of said gun bore and firing means forfiring a charge in said firing charge chamber, said firing means beindisconnected when said body sections are disconnected and beingconnected for operation when said body sections are connected; and aplurality of projectiles, one each of which is disposed in one of saidgun bores.

7. In a perforating gun of the type adapted to be lowered into a wellcasing, the combination of: a plurality of gun body sections with meansfor securing said sections in end to end relation; certain of saidsections each having means forming a gun bore extending out through aside wall thereof and a powder chamber formed in an end thereof andcommunicating with the inner portion of said gun bore, there being wallmeans positioned to close the outer end of said chamber when saidsections are connected in end to end relation; and means for firingcharges in said powder chambers.

8. In a perforating gun of the type adapted to be lowered into a wellcasing, the combination of: a plurality of gun body sections with meansfor securing said sections in end to end relation, certain of saidsections each having means forming a gun bore extending out through aside wall thereof and a powder chamber formed in an end thereof andcommunicating with the inner portion of said gun bore, there being wallmeans positioned to close the outer end of said chamber when saidsections are connected in end to end relation; means for firing a chargein a selected one of said powder chambers; and means connecting saidselected chamber to other of said chambers to explode charges therein.

9. In a perforating gun of the type adapted to be lowered into a wellcasing, the combination of: a plurality of gun body sections with meansfor securing said sections in end to end relation, certain of saidsections each having means forniing a gun bore extending out through aside wall thereof and a powder chamber formed in an end thereof andcommunicating with the inner portion of said gun bore, there being wallmeans positioned to close the outer end of said chamber when saidsections are connected in end to end relation; means for firing a chargein a selected one of said powder chambers; and means extendinglengthwise of the assembly of connected body sections operating to firecharges in the remaining' sections in consequence of the firing of thecharge in said selected chamber.

10. For use in a perforating gun of the character described: a gun bodysection having connecting means at the ends thereof, means forming a gunbore extending out through a side thereof, a powder chamber between saidbore and one end of said body, said powder chamber communicating withthe inner portion of said bore and also being in communication with saidend of said body to enable a charge to be placed therein, and a passageextending to the other end of said body, said passage communicating withsaid powder chamber 11. For use in a perforating gun of the characterdescribed: a gun body section having connecting means at the endsthereof, means forming a gun bore extending out through a side thereof,a powder chamber communicating with the inner end of said gun bore andalso having communication with one of said ends of said body, and apassage extending to the other end of said body, said passagecommunicating with said powder chamber.

12. For use in a perforating gun of the character described: a gun bodysection having connecting means at the ends thereof, means forming a gunbore extending out through a side thereof, a powder chambercommunicating with the inner end of said gun bore and also havingcommunication with one of said ends of said body, and a passageextending to the other end of said body, said passage communicating withsaid powder chamber, and a restraining 'member replaceably secured insaid passage.

13. For use in a perforating gun of the character described: a gun bodyhaving a plurality of spaced gun bores extending out through the sidewall thereof, a powder chamber communicating with the inner end of eachof said gun bores, there being passage means serially connecting saidpowder chambers; means for firing the charge in one of said powderchambers; and restraining means in said passage means between saidpowder chambers.

14. In a perforating gun of the type adapted to be lowered into a wellcasing, the combination of: a gun body comprising a plurality ofsections connected in end to end relation, said sections each having agun bore, a powder chamber to receive a firing charge communicating withsaid gun bore, there being passage means in the several sections toserially connect said powder chambers when said sections are connectedtogether; a restraining member in each of said passage means insertablein operative position through the ends of said sections when saidsections are disconnected; and means for igniting a charge in at leastone of said powder chambers.

15. In a perforating gun of the character described, the combination of:a body having serially arranged gun bores and cooperating chambersconnected individually to said gun bores to re ceive propellant powdercharges; means to ignite a powder charge in at least one of saidchambers; and serial firing means connecting said chambers, each of saidfiring means receiving at least a portion of the blast resulting fromthe burning of a powder charge in one of the chambers to which it isconnected and in consequence thereof causing ignition of the powdercharge in the other of the chambers to which it is connected.

16. In a perforating gun of the type adapted to be lowered into a wellcasing, the combination of a gun body comprising a plurality of sectionssecured by box and pin joints, each of said sections having a gun boreleading out through a side thereof, a powder chamber formed at thebottom of the box thereof to receive a firing charge, a passageconnecting said powder chamber with said gun bore, and an ignitionpassage extending through the pin thereof to connect said powder chamberto the powder chamber of an adjacent section; and means for firing acharge in at least one of said powder chambers.

17. In a perforating gun of the type adapted to be lowered into a wellcasing, the combination of: a gun body comprising a plurality ofsections secured by box and pin joints, each of said sections having agun bore leading out through a side thereof, a powder chamber formed atthe bottom of the box thereof, a passage connecting said powder chamberwith said gun bore, an ignition passage' extending through the pinthereof to connect said powder chamber to the powder chamber of anadjacent section, and a removable restraining member in said passageexposed at the end of said pin for removal when said pin is unscrewedfrom its cooperating box.

18. In a perforating gun of the type adapted to be lowered into a wellcasing, the combination of: suspension means having a threaded pinprojecting downward therefrom; an upper gun body section having athreaded box screwed on to said pin, an opening leading downward fromsaid box to form a powder chamber, a gun bore below said powder, chamberand having its inner end connected to said powder chamber, a threadedpin projecting downward from said section, and an ignition passageleading upward from the lower face of said last named pin, said passagecommunicating with said powder chamber; a plurality of succeeding gunbody sections connected in consecutive order to said upper body section,each of said succeeding sections being substantially counterparts ofsaid upper section; and means for firing a charge in said powder chamberof said upper gun body section, said firing means including a firing pinextending through said threaded pin of said suspension means and meanscarried by said suspension means for actuating said firing pin.

19. In a perforating gun of the type adapted to be lowered into a wellcasing, the combination of: a gun body having a laterally directed gunbore for a projectile and means for holding a firing charge in operativeposition relative to said projectile; suspension means for said gun bodyextending upward therefrom, said suspension means comprising a lowerportion and an upper portion; and firing means for said chargecomprising a firing pin extending longitudinally in said lower portionof said suspension means, an anvil movably supported on the upperportion of said suspension means so as to be driven down by a suitablehammer against said firing pin; lock means for said firing pin mountedon said lower portion of said suspension means so as to be engaged withsaid firing pin, said lock means comprising a resiliently supported dogarranged to be moved into engagement with said firing pin; and actuatingmeans for said lock means comprising a sleeve slidable on said lowerportion of said suspension means for moving said dog into engagementwith said firing pin when said sleeve is lowered on said lower portionof said suspension means, a sleeve slidably disposed around the upperportionof said suspension means; and resilient pipe engaging meansconnecting said sleeves.

20. In a perforating gun oi the type adapted to be lowered into a wellcasing, the combination of: a gun body having a laterally directed gunbore fora projectile and means for holding a firing charge in operativeposition relative to said projectile; suspension means for said gun bodyextending upward therefrom; firing means for said charge comprising afiring pin having an engageable portion; lock means for said firing pinhaving an engager normally supported out of engagement. with saidengageable portion of said firing pin; actuating means for said lockmeans comprising a member slidable on said gun body for relativemovement between raised and lowered position, said actuating meanseflectuating movement of said engager into position for engagement withsaid engageable portion of said pin when said actuating means is in saidlowered position; and means operative to move said actuating means intosaid lowered position.

21. In a perforating gun of the type adapted to be lowered into a wellcasing, the combination of: a gun body having a laterally directed gunbore for a projectile and means for holding a firing charge in operativeposition relative to said projectile; suspension means for said gun bodyextending upward therefrom; firing means for said charge comprising afiring pin having an engageable portion; lock means for said firing pinhaving an engager normally supported out of engagement with saidengageable portion or said firing pin; and actuating means operating inconsequence of upward movement 01' said gun body in a pipe in said wellto effectuate engagement of said engager with said engageable portion ofsaid pin.

22. In a perforating gun of the type adapted to be lowered into a wellcasing, the combination 01': a gun body having a laterally directed gunbore for a projectile and means for holding a firing charge in operativeposition relative to said projectile; suspension means for said gun bodyextending upward therefrom; firing means for said charge whereby thesame may be fired when the gun is in the well, said firing meanscomprising a member which moves between raised and lowered position andhas a downwardly faced shoulder; a blocking element supportedon said gunbody for movement into a position under said shoulder whereby to preventdownward movement of said-member; and actuating means operative to movesaid blocking element into said position under said shoulder.

IRA J. McCULDOUGI-I.

